A number of arrangements are known in the prior art which are for the purpose of protecting a stethoscope head against contamination. These prior art devices range from simple to complex.
U.S. Pat. No. 4,871,046, issued Oct. 3, 1989, discloses a disposable shield for stethoscope heads in the form of an envelope which is constructed from a single piece of plastic material in which the sides are folded toward each other, thereby defining two top portions overlaying a bottom portion. The edges are sealed as by heat sealing.
The disposable shield or cover of U.S. Pat. No. 4,871,046 is essentially in the form of an envelope which relatively loosely receives the stethoscope head. This approach allows excess material below, about and above the stethoscope head. This excess plastic sheet material can distort and move relative to the head when employed, thus creating extraneous sounds which adulterate and interfere with the sounds from the patient being transmitted to the stethoscope user.
U.S. Pat. No. 4,461,368,issued Jul. 24, 1984, discloses a cover for a stethoscope having a flexible membrane of latex and a rigid rim member. Such an arrangement is relatively complex and expensive and does not particularly lend itself to disposal and replacement after a single use. Furthermore, employment of several parts which must be secured together increases the likelihood of adulterating sounds and vibrations being introduced to the stethoscope.
Applicant is also aware of the following United States Patents which are believed to be further representative of the state of the prior art: U.S. Pat. No. 4,867,268, issued Sep. 19, 1989, U.S. Pat. No. 4,867,265, issued Sep. 19, 1989, U.S. Pat. No. 3,867,925, issued February 25, 1975, U.S. Pat. No. 3,614,991, issued Oct. 26, 1971, U.S. Pat. No. 3,543,875, issued Dec. 1, 1970, U.S. Pat. No. 3,255,841, issued Jun. 14, 1966, U.S. Pat. No. 3,213,960, issued Oct. 26, 1965, U.S. Pat. No. 2,651,380, issued Sep. 8, 1953, U.S. Pat. No. 5,054,063, issued Oct. 1, 1991, U.S. Pat. No. 2,650,269, issued Aug. 25, 1953, and U.S. Pat. No. 2,507,375, issued May 9, 1950.